I bought a "cheap" Trust Webcam (Spotlight 16429 - 0x62c0 0x0c45) and tried to use it on my OpenBSD 5.0 machine, with no success.
The cam is recognized only as ugen device and not as video device.
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ugen0 at uhub0 port 1 "Trust Webcam Trust Webcam" rev 2.00/1.00 addr 3
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So, is there a way to tell the uvideo driver, that this is an compatible device ?

Supported USB devices are managed in three files: sys/dev/usb/{usbdevs.h,usbdevs_data.h,usbdevs} -- see the instructions in usbdevs for adding this device to the list of Trust products. As described in the instructions, you will still need to modify the appropriate driver's probe to match the device.

FYI: only two Trust products are listed in -current, which is beyond the upcoming 5.2 release:

Be aware that OpenBSD 5.2 is slated to be released in November which means that OpenBSD 5.0 will no longer be officially supported.

Yes, the risk and the effort are high, because of dependencies to php (versions).
I choosed OpenBSD for my server-os because of small requirements and security. So I hope(ed) I can use an version for more than some months.